/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.aggregation.timerangeiterator;

import org.apache.iotdb.tsfile.read.common.TimeRange;

/**
 * This interface used for iteratively generating aggregated time windows in GROUP BY query.
 *
 * <p>It will return a leftCloseRightClose time window, by decreasing maxTime if leftCloseRightOpen
 * and increasing minTime if leftOpenRightClose.
 */
public interface ITimeRangeIterator {

    /**
     * return the first time range by sorting order
     */
    TimeRange getFirstTimeRange();

    /**
     * @return whether current iterator has next time range
     */
    boolean hasNextTimeRange();

    /**
     * return the next time range according to curStartTime (the start time of the last returned time
     * range)
     */
    TimeRange nextTimeRange();

    boolean isAscending();

    default TimeRange getFinalTimeRange(TimeRange timeRange, boolean leftCRightO) {
        return leftCRightO
                ? new TimeRange(timeRange.getMin(), timeRange.getMax() - 1)
                : new TimeRange(timeRange.getMin() + 1, timeRange.getMax());
    }

    /**
     * As there is only one timestamp can be output for a time range, this method will return the
     * output time based on leftCloseRightOpen or not.
     *
     * @return minTime if leftCloseRightOpen, else maxTime.
     */
    long currentOutputTime();

    long getTotalIntervalNum();
}
